The impact of electrolyte and urea on the phase separation of Triton X-100

Abstract

Abstract The temperature dependent phase separation of non-ionic surfactants is the most important characteristic of non-ionic surfactants. Herein, phase separation of Triton X-100 (TX-100) has been investigated in electrolytes and urea medium. The cloud point (CP) of TX-100 increases with the augment of the concentration of TX-100 in the electrolyte medium whereas decrease slightly with the rise of the concentration of TX-100 followed by increase with the subsequent rise of concentration in the urea medium. The CP values of TX-100 reduce in the electrolyte medium and augment in the urea medium as compared to aqueous medium. The positive values of free energy of clouding (∆Goc) signify the non-spontaneous phase separation of TX-100 in all cases. The values of enthalpy change (∆Hoc) as well as entropy change (∆Soc) of clouding were positive which reduce with the rise of TX-100 concentration and appear to be negative at the highest concentration of TX-100 employed herein in the electrolyte/urea mediums in almost all cases. The free energy of transfer (∆Goc,tr) were negative in electrolyte medium whereas positive in urea medium. The other thermodynamic properties of transfer as well as entropy-enthalpy compensation parameters were also assessed and explained with proper clarification.